Rechargeable batteries are increasingly replacing single use batteries due to economic, performance convenience and environmental factors. Rechargeable batteries have been integrated into electric devices, such as cordless toothbrushes, for some time. Such devices typically locate the device with respect to a charger to ensure good coupling for efficient power transfer.
There is a demand for wirelessly rechargeable batteries to be provided in a standard battery casing. There is limited space within the casing for the electrochemical cell, charging circuit and coils. Further it would be desirable to be able to charge a battery in any orientation within a general charging region and when located within an electronic device.
Batteries are typically housed in an orientation parallel or orthogonal to the faces of an electronic device. Power transmitters in the form of charging mats etc. typically generate a field normal to the charging surface. Thus in some orientations there may be limited coupling between the coils within a wirelessly rechargeable battery and the coils of the power transmitter. Power transmitters may also be wasteful in generating a full charging field whether batteries are present or not.
It is an object of the invention to provide a battery and/or power transmitter enabling charging in all typical orientations in an energy efficient manner or to at least provide the public with a useful choice.